Question: Reduce to lowest terms: $- \dfrac{9}{5} \div \dfrac{2}{7} = {?}$
Solution: Dividing by a fraction is the same as multiplying by the reciprocal of the fraction. The reciprocal of $ \dfrac{2}{7}$ is $ \dfrac{7}{2}$ Therefore: $ - \dfrac{9}{5} \div \dfrac{2}{7} = - \dfrac{9}{5} \times \dfrac{7}{2} $ $ \phantom{- \dfrac{9}{5} \times \dfrac{7}{2}} = \dfrac{-9 \times 7}{5 \times 2} $ $ \phantom{- \dfrac{9}{5} \times \dfrac{7}{2}} = \dfrac{-63}{10} $